Method of stretching metal rods



Nov. 15, 1938. A. H. BORWICK METHOD CF STRETCHING METAL RODS Filed Sept.11, 1935 l atented Nov. 15, 1938 UNITED STATES PATENT OFFICE ApplicationSeptember 11, 1935, Serial No. 40,066

4 Claims.

My invention relates to a method of andapparatus for stretching metalrods in order to straighten the same, for increasing the tensilestrength of the rod and increasing the resistance 5 of the rods tobending strains or stresses, also for the purpose of removing scale,rust and the like from the surface of the rod and also for the purposeof materially increasing the usable lengths of the ordinary commercialrods that are received from the mill.

The principal object of my invention is, to provide a relatively simpleand easily practiced method whereby metal rods, particularly of the typeutilized as a support for curtains and the like, may be conveniently andeconomically stretched and straightened while said rods are cold andafter the same have been delivered by the mill to the shops or factorieswhere the rods are cut into proper lengths and treated so as to be soldin the open market for use as curtain supporting rods. 7

Metal rods of the type used in the production of curtain rods, whendelivered by the mill to the curtain rod shops or factories, are to agreater or lesser degree, covered with rust and scale that accumulatesduring storage and transit and said rods are generally bent as a resultof rough handling during transportation and it is one of the principalobjects of my invention to provide a relatively simple apparatus forsimultaneously straightening the rods and removing the scale and rusttherefrom prior to the cutting of the rods into the desired lengths foruse as curtain supporting rods.

A further object of my invention is, to stretch the rods for the purposeof materially increasing the usable length of the rods as they arereceived from the mill and in practice I have by means of the apparatusherein shown and described stretched one-half inch square twenty footlength metal rods, eighteen inches and which stretching operationmaterially increases the tensile strength of the rod and at the sametime materially increase its resistance to bending strains. and theconsequent increase of tensile strength and resistance to bendingstrains I am able to provide rods of considerable length which whensupported by suitable brackets adjacent to their ends, will supportrelatively heavy curtains and like hangings without the requirement foran intermediate support or bracket, thereby eliminating the expense ofsuch intermediate bracket and its installation and at the same timeprovid- As a result of this stretching of the rodsing a much morepresentable support for the curtain.

With the foregoing and other objects .in view my invention consists incertain, novel features of construction and arrangements of parts thatwill 5 be hereinafter more fully described and claimed and illustratedin the accompanying drawing in which:

i Fig. 1 is a plan view of a relatively simple form of apparatus that Ihave designed for carrying 10 out my improved method of stretching metalrods.

Fig. -2 is a vertical section partly in elevation, taken on the line 2-2of Fig. 1.

Fig. 3 is an enlarged cross section taken on the line 3-3 of Fig. 1.

Referring by numerals to the accompanying drawing which illustrates apractical form of apparatus which may be used for practicing my improvedmethod, l0, l0 designate a pair oi parallel rails which are connected atsuitable points by cross members such as H and the entire structurebeing supported by suitable legs l2.

Rigidly mounted on one end of the frame between the rails I0, is acylinder l3, within which operates a piston l4 and said piston beingcarried by a piston rod I5 that extends through the rear end of cylinderi3.

Carried by the proiecting 'end of the piston rod,- is a cross head i6.

Located adjacent to the cylinder, is a pump [1,

preferably of the rotary type and leading from said pump to the ends ofthe cylinder, are pipes l8 and I9.

Located between the pipes l8 and I9 and the pump II, is a valve 20,which controls the flow of fluid between the pump and cylinder and thevalve may be provided with a by-pass for the fluid acted upon by thepump while the piston within the cylinder is at rest.

The fluid utilized in the apparatus as shown 49 and described may be 011or any other relatively heavy liquid.

Connected to the ends of cross head It, are rods 2| that extend alongthe sides of the cylinder l3 and the forward ends of said rods areconnected to a cross head 22. This cross head is connected in anysuitable manner, preferably by means of short rods 23, to a block 24that is mounted for sliding movement on the rails l0 and connected tothe underside of this block and 50 to one of the cross members ll of theframe of the apparatus, is a retractile spring 25 that yieldinglyresists the movement of block 24 toward the cylinder II.

Arranged for sliding movement in the upper 6biockltisapairofwedgesllhavformedontheiradiacent verticalRigidlyflxedontheendsoftherails ilopposite the ends that supportcylinder II, is a block it, in which is arranged for sliding movement aof wedges I! provided on their adjacent vertical faces with teeth II.

In practicing my improved method with the apparatus Just described, oneend of the rod R to be stretched and straightened, is engaged betweenthe toothed faces of the wedgu II and the other end of the rod isengaged between the toothed faces of the wedges II, it being understoodthat when the rod is thus engaged by the pairs of wedges, the block 24is at the forward end of its travel with piston ll near the forward endof its travel in cylinder ll.

Valve II is now manipulated so that fluid passes from pump I! throughpipe II to the forward end of the cylinder and following such action the.piston will be slowly moved rearwardly through the cylinder and thefluid to the rear of the piston willpassthrough pipe iltopump ii. I

Through the connections I, II, 22 and II, block 24 will be drawn towardthe cylinder, thereby stretching rod B. one end of which is flrmlygripped between the wedges II that are arranged in stationary block IIand during this stretching operation practically all scale and rust onthe surface of the rod will be broken and dislodged therefrom and at thesame time all bends and kinks will be removed from the rod so that thesame is perfectly straight at the termination of the stretchingoperation.

It has been demonstrated by tests and experiments. that the stretchingof the rod as just described, stretches and straightens the flbers andcompacts the molecules of metal within the rod, so as to materiallyincrease its tensile strength and also to materially increase itsresistance to bending strains.

As a matter of fact laboratory tests show that a hot rolled mild r steelrod twenty feet in length, one-half inch square when stretched eighteeninches in accordance with my improved method, shows an increase instrength as measured by yield points of 32.6 percent, an increase intensile strength of 8.8 percent and with a decrease in cross sectionaldimensions of only .008 percent.

After the stretching operations as just described have beenaccomplished, the valve 2. is

shifted to its normal position so as to by-pass the fluid from one sideof the'pump through the valve to the other side and to establish directcommunication between the pipes II and II and after the stretched, scalefree rod has been removed from the machine, the power stored in coilspring ll will act to draw block 24 back to its normal forward position,during which movement the fluidwill pass from the chamber in cylinder I!in front of piston ll through pipes II and II to the chamber within thecylinder behind said piston,

While I have described my improved method and apparatus as beingparticularly designed for increases the tensile strength of the rods andalso increases the resistance of the rods to bending strains or stressesand also materially increases the usable lengths of the ordinarycommercial rods that are produced by the mill.

Inasmuch as the rods when stretched in, accordance with my method, arefree from scale and rust, they may be flnished with a coating of lacqueror the like without resorting to the usually employed methods ofremoving scale, rust and the like, thereby materially lessening the costof production of the flnished rods.

I claim as my invention:

1. The herein described method of stretching hot run metal rods toproduce drapery supporting rods, which consists in clamping and rigidlyholding one end of a rod and then gripping the other end of said rod andpulling same away from the rigidly held end so as to subject said rod totensional strains and stretch same to a sufflcient degree to break andremove all scale and rust from the external surfaces of the rod.

2. The herein described method of stretching commercially produced hotrun metal rods. to produce drapery supporting rods, which consists inanchoring one end of a rod and then gripping the other end of said rod,stretching same away from its anchored end sufllcient to break anddislodge all scale and rust from the surfaces of said rod.

3. The herein described method of stretching commercially produced hotrun metal rods to produce drapery supporting rods which consists inclamping and rigidly holding one end of a rod and then gripping theother end of said rod and pulling the same away from the rigidly heldend so as to subject said rod to tensional strains sufficient to stretchsaid rod and to produce a straightening and permanent elongation thereofand to break and dislodge all scale and rust from the surfaces of therod.

4. The method of removing scale from hot rolled steel rod and the likewhich comprises gripping opposite ends of the rod in gripping devicesand causing one gripper device to move away from the other to subjectthe rod to a tensile stress sumcient to permanently elongate said rod ina single uninterrupted movement and to stress the scale on the rodbeyond the breaking point of the scale whereby the scale will break upand be freed from the rod.

' ARTHUR H. BORWICK.

